Matt
Quickest (but not cheapest!) way is to get Spamassassin off the email email onto a dedicated box. SA is a real CPU hog.
Other thing to look at is tuning SA (which is prob a good idea anyway).
See following link for my recommendations..
http://wiki.mailscanner.info/doku.php?id=maq:index#getting_the_best_out_of_spamassassin
contains some tuning tips...
--
Martin Hepworth
Snr Systems Administrator
Solid State Logic
Tel: +44 (0)1865 842300
> -----Original Message-----
> From: exim-users-bounces@??? [mailto:exim-users-bounces@exim.org] On
> Behalf Of Matt
> Sent: 01 March 2008 18:49
> To: exim-users@???
> Subject: [exim] Speeding Up Exim
>
> > I just got a call from someone wanting to be able to send 50k email
> > messages a second. Most of it in bursts of a few seconds long. It has to
> > do with some kind of gaming application. I'm just trying to picture in
> > my mind what kind of hardware could do that.
>
> I have an Directadmin based email/web server. Its based on CentOS
> 32bit 4.4, Exim, Dovecot, Spamassassin-3.2.4, Clamav and etc. Maildir
> based.
>
> Hardware is:
> AMD64 Dualcore 3800+ just updated to 5600+
> 4Gbyte DDR2
> SATA2 500GB drive
>
> Normally load average is like 8 or less but at peak times I am seeing
> it spike to like 100 area. Upgrading the CPU gained very little. I
> am thinking I am disk I/O bottle necked. I have about 2000 email
> accounts and according to eximstats at peak times I am seeing
> "Messages received per hour" of 40K.
>
> I have added a few scripts hoping they would help. I now auto suspend
> email accounts that have not been checked in 6 months. Few other
> scripts for cleaning out old high scoring spam from mailboxes
> infrequently checked. Also bounce based on a few blacklists at MTA
> time. Cannot be too aggressive there else users complain.
> Spamassassin does a very good job. Very rarely does a false positive
> but does let some SPAM slip by.
>
> Any other ideas to speed it up at peak times? Hopefully without
> starting from scratch with crud load of downtime.
>
> I wander if the SATA feature of NCQ would speed the disk I/O up but
> there is likely no easy way to upgrade CentOS 4.x to do that.
>
> Matt
>
> --
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